Reverse a Singly Linked List

Last Updated: 06 October, 2024 🕓 5 Mins

In this Linked List tutorial, we will see all about the reverse a linked list.

Example: If list contains 5 nodes

Input: 10 -> 20 -> 30 -> 40 -> 50
Output: 50 -> 40 -> 30 -> 20 -> 10

To reverse a linked list, there are two approaches:

Iterative Approach

Recursive Approach

Reverse a linked list using Iterative approach

    
  // Java program to reverse a linked list using Iterative approach
  public class Node {
    int data;
    Node next;
  
    // Constructor
    Node(int data) {
      this.data = data;
      this.next = null;
    }
  }
  
  public class ReverseUsingIterativeApproachInSLL {
    // Method to reverse a list
    static Node reverseList(Node head) {
  
      // Initialize three pointers: currNode, prevNode and nextNode
      Node currNode = head, prevNode = null, nextNode;
  
      // Traverse all the nodes of Linked List
      while (currNode != null) {
  
        // Store next
        nextNode = currNode.next;
  
        // Reverse currNodeent node's next pointer
        currNode.next = prevNode;
  
        // Move pointers one position ahead
        prevNode = currNode;
        currNode = nextNode;
      }
  
      // Return the head of reversed linked list
      return prevNode;
    }
  
    // Method to print a linked list
    static void printList(Node node) {
      while (node != null) {
        System.out.print(" " + node.data);
        node = node.next;
      }
    }
  
    public static void main(String[] args) {
      // Create a linked list
      Node head = new Node(10);
      head.next = new Node(20);
      head.next.next = new Node(30);
      head.next.next.next = new Node(40);
      head.next.next.next.next = new Node(50);
  
      // Linked list will be created like this
      // 10 -> 20 -> 30 -> 40 -> 50
  
      System.out.print("Original Linked list:");
      printList(head);
  
      head = reverseList(head);
  
      System.out.print("\nReversed Linked List:");
      printList(head);
    }
  }

Output

Original Linked list: 10 20 30 40 50
Reversed Linked List: 50 40 30 20 10

Reverse a linked list using Recursive approach

    
  // Java program to reverse a linked list using Recursive approach
  public class Node {
    int data;
    Node next;
  
    // Constructor
    Node(int data) {
      this.data = data;
      this.next = null;
    }
  }
  
  public class ReverseUsingRecursiveApproachInSLL {
    // Method to reverse a list
    static Node reverseList(Node head) {
  
      // If we reached the last node means list is empty, 
      // simply return the head of list
      if (head == null || head.next == null)
        return head;
  
      // reverse the rest of linked list and put the first
      // element at the end
      Node rest = reverseList(head.next);
  
      // Make the current head as last node of remaining
      // linked list
      head.next.next = head;
  
      // Update next of current head to NULL
      head.next = null;
  
      // Return the reversed linked list
      return rest;
    }
  
    // Print a linked list
    static void printList(Node node) {
      while (node != null) {
        System.out.print(" " + node.data);
        node = node.next;
      }
    }
  
    public static void main(String[] args) {
      // Create a linked list
      Node head = new Node(10);
      head.next = new Node(20);
      head.next.next = new Node(30);
      head.next.next.next = new Node(40);
      head.next.next.next.next = new Node(50);
  
      // Linked list will be created like this
      // 10 -> 20 -> 30 -> 40 -> 50
  
      System.out.print("Original Linked list:");
      printList(head);
  
      head = reverseList(head);
  
      System.out.print("\nReversed Linked List:");
      printList(head);
    }
  }

Output

Original Linked list: 10 20 30 40 50
Reversed Linked List: 50 40 30 20 10